The rock is a dark-green peridotite (kimberlite) composed of serpentinized olivine and a number of accessory minerals, including phlogopite, pyrope, calcite, enstatite, magnesian ilmenite, and others.
Minor minerals and mineral groups in peridotite include plagioclase, spinel (commonly the mineral chromite), garnet (especially the mineral pyrope), amphibole, and phlogopite.